I have an object array, and I want to test if one of them has a data-attr so I could make a simple if statement, here is an example of what I'm trying to do
if (array.hasAttribute("data-attr")) {}
I'm tried some() and every()
if (array.some(this.hasAttribute("data-attr"))) {}
but I can't figured out the right syntax, please help
array.some(this.hasAttribute("data-attr"))
Was almost correct. Array#some takes a predicate, so you need to do
array.some(function(el) {
return el.hasAttribute("data-attr");
})
Or shorter using arrow functions:
array.some(el => el.hasAttribute("data-attr"))
Array#every works the same way and takes a predicate, so you can call it the same way:
array.every(function(el) {
return el.hasAttribute("data-attr");
})
//or
array.every(el => el.hasAttribute("data-attr"))
And if you want to use one or the other, you can extract the predicate and re-use it:
var hasDataAttribute = el => el.hasAttribute("data-attr")
array.some(hasDataAttribute)
array.every(hasDataAttribute)
If you have jQuery objects, you have to use some tricks since jQuery doesn't have a method that returns true or false for the existence attributes. You can easily simulate it with obj.attr('some-attribute') !== undefined - this will return true if some-attribute exists and false if it doesn't.
var hasDataAttribute = jQueryEl => jQueryEl.attr('data-attr') !== undefined
For data-* attriutes, you can also use jQuery.data() which is (in this case) a shorthand element.attr('data-something') is the same as element.data('something'):
var hasDataAttribute = jQueryEl => jQueryEl.data('attr') !== undefined
array is a jQuery object, array.filter('[data-attr]').length is one approach @jay_dtr
some only ensures that at least one element has that attribute, every requires that all elements do.